Figure 1
![Figure 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2F1756-0500-6-158/MediaObjects/13104_2013_Article_2183_Fig1_HTML.jpg)
ECG strip demonstrating timing of image acquisition. PTAS CTA is shown with radiation exposure peak at 100% of the reference tube current (red arrow, “Range” settings) at 300–400 msec and a “plateau” (green arrow, “Scan” settings) with 20% of the reference tube current to capture additional phases at mid and late systole/early diastole.